Time of Death The Face of Death All

Time of Death

The Face of Death

"All I desire for my own burial is not to be buried alive. " - Lord Chesterfield, 1769 n 17 th Century – Coma or weak heartbeat = DEAD and BURIED – Fear of being buried alive bell in coffin § “Saved by the bell”

"Have me decently buried, but do not let my body be put into a vault in less than two days after I am dead. " deathbed request of George Washington. n Waiting Mortuaries – Established in 17 th century – Those thought to be dead…placed on cots and observed until body began to rot § Now…. they’re dead

n Is a person with a heartbeat alive even if there is no brain activity? – What do you think?

Cessation (Death – End of Life) n Somatic death – Death of the entire body – Legal definition: § Death of upper brain & brain stem n Cellular death – Death confined to cells or tissues in the body “Irreversible cessation of circulation of blood. ”

n Lend me a looking glass; If that her breath will mist or stain the stone, Why then she lives. Shakespeare, King Lear

Autolysis n When a cell dies, it breaks down – Breakdown = autolysis § Definition: the destruction of a cell through the action of its own enzymes n Once enough cells begin autolysis, life cannot be restarted – Cell membrane dissolves – enzymes and other cell contents spill – digest surrounding tissues

Manners of Death n Natural – death results from natural disease processes n Accidental – Caused by unplanned events n Suicidal – Person purposefully kills oneself n Homicide – Caused by another person n Undetermined

Categorize Manner of Death n A man with a heart condition is attacked and dies from a heart attack during the assault – Accident or homicide? n An elderly woman dies after being kept from receiving proper health care by her son. – Natural or homicide? n Both cases = homicide. Proving in court that manner of death was a homicide may be difficult

Cause of Death n Cause of death = reason someone dies n “Proximate cause of death” – refers to an underlying cause of death… rather than FINAL cause of death – Ex: If someone is exposed to large amounts of radiation and then developed cancer § Proximate cause of death? – Radiation exposure!

Mechanism of Death n Mechanism of Death = the specific change in the body that brought about the cessation of life – Ex: If cause of death is shooting, what would be the mechanism of death? § Loss of blood, cessation of brain function or exsanguination (total blood loss) – Ex: If cause of death is heart attack, what would be the mechanism of death? § Heart stopping to beat or pulmonary arrest

Estimate Time of Death n Evaluate the stage of decomposition that the body was found in

Rigor Mortis: Rigidity of Death In mammals n Body stiffening of muscles in the position that they are in when death occurs n First eyelids, neck, jaw, then other muscles (from head to toe) n

Rigor Mortis n How? – Aerobic respiration stops, anaerobic respiration begins § Conversion of sugar to pyruvic acid to lactic acid § 2 ATP anaerobic vs. 36 ATP aerobic – Lack of ATP forces muscles to stay contracted

Rigor Mortis Inside cell n Ca 2+ naturally flow from fluid surrounding muscle cells to inside the cell n To relax muscles, Ca 2+ must flow back across the cell membrane – Requires ATP energy, not enough ATP after death – Muscles stay contracted Fluid surrounding muscle cells

Rigor Mortis n Timeline – Begins 3 -4 hours after death – Maximum stiffness 12 hours after death – Stiffness decreases until 72 hours after death

Cadaveric Spasms n Occurs at the moment of death n Most common when person has died violently n Involves a certain group of muscles – hand, forearm

Livor Mortis “Death Color” n Lividity – Dark purple discoloration of the skin resulting from the gravitational pooling of blood to the lowest points of the body § Dependent on body position – In deaths from carbon monoxide poisoning, it is classically described as "cherry red“ – Onsets immediately

Livor Mortis n Duality of distribution – After 10 -12 hours lividity becomes “fixed” – If body is moved there will be a dual lividity pattern

Livor mortis

• What assumptions can be made about the victim based on lividity? • If this victim was found upright in a chair, what else can be assumed?

• In average environmental conditions/temperatures, a few simple rules of thumb can be helpful: Bernard Knight’s Formula Body Condition PMI Warm and flaccid < 3 hours Warm and stiff 3 -8 hours Cold and stiff 8 -36 hours Cold and flaccid > 36 hours

Algor Mortis “Death Heat” “The Chill of Death” n Most useful single indicator of time of death within 24 hours post mortem n “Body Cooling” – Estimated that the body temperature drops approximately 1. 5 F/hour n Cooling effected by: – Location, weather, clothing, activity at death, victim size

Algor Mortis n To find the standard temperature of a corpse, a thermometer is inserted into the liver – Why the liver? Standard location so investigators can compare results

Eye Part Open/Clos ed Onset Corneal film Open minutes Closed hours Scleral discoloration Open Minutes-hours Cornea cloudiness Open 2 hours Closed Up to 24

Aqueous Humor n Clear, watery fluid in the eye n Can measure the amount of potassium (K+) in the aqueous humor to determine time of death n K+ amounts increase for up to 104 hours after death n Temperature at time of death effects K+ levels

Stomach Contents n Shows nature of last meal & abnormalities n Stomach starts to empty within 10 minutes n If the victim had a… – Light meal: will stay in stomach 1 -2 hours – Medium meal: will stay in stomach 3 -4 hours – Large meal: will stay in stomach 4 -6 hours n Emotional state effects stomach emptying

PMI Definition Onset* Loss* External Factors Rigor Mortis Muscular contraction 3 -12 hrs 72 hrs > Temp = > rate of Rigor mortis < Temp = < rate of Rigor mortis Livor Mortis Pooling of blood; 30 min - lividity 2 hrs /hypostasis 6 -12 hrs it becomes fixed** Body position, weight, skin color, body temperature, toxicity Algor Mortis Cooling of body Ocular Changes Corneal Film Minutes-hrs Sclera Discolored Minutes-hrs Cornea Cloudy 2 -24 hrs Cornea Opaque 3 days Light 0. 5 -2 hours to empty Medium 3 -4 hours to empty Heavy 4 -6 hours to empty Changes Stomach Contents ↑ Temp = ↑ rate of algor mortis ↓ Temp = ↓ rate of algor mortis Clothing/covering of body will slow the process; environmental conditions must be considered Eyes open or closed Caloric content, age, psychological state/stress levels, disease, when they last ate, what they ate, etc.